Sitting on the train heading back from New York to Washington D.C., gazing out of the window at stressed watersheds, I had some time to reflect on a very special Climate Week. What does it all add up to? Where does it leave us as a global community needing speed and scale in our climate action?

Much is being written. Let me add a perspective. Here are three thoughts amid my swirl of memories, moments and impressions.

Climate osmosis – the street reaches the hallowed halls

It was difficult to stand in the canyon that is 6th Avenue, with a sea of people stretching in both directions – environmental activists, nurses, pensioners, business people, every possible faith community, moms, a sprinkling of celebrity and a dash of statesmen – and not be moved. On the Sunday before the Summit, more than half a million people took to the streets in People’s Climate Marches in New York and more than 160 countries across the globe. The marchers demanded climate action from their leaders, suggesting that the politics of climate action, once considered too hard to handle, might no longer be as difficult as leaders think.

The reverberations continued for 48 hours and became a point of reference in almost every speech at the UN Secretary-General’s Climate Leadership Summit. More than 120 heads of state and government came to hint and in some cases pledge action on climate change. New coalitions of governments, businesses, investors, multilateral development banks and civil society groups announced plans to mobilize over $200 billion for low-carbon, climate-resilient development. Forests and cities were big winners, landing pledges of around $450 million for forests and bringing together more than 2,000 cities in a new Compact of Mayors to help improve accounting of urban greenhouse gas emissions and the actions cities are taking to reduce them.